Various types of steam irons are known mainly consisting of a water reservoir which by means of a closing valve is connected to a steam generating space formed by a recess in the heating plate. The steam generating space is connected to the exterior by means of a number of small openings provided in the heating plate.
It is known that the quantity of steam which has to be supplied to the material to be ironed varies according to the kind of material, the average of it being equal to about 20% of the total amount of liquid which can be absorbed by the material. To obtain a good ironing operation furthermore it is necessary that this takes place at a previously selected temperature which varies according to the kind of material.
In order to obtain the temperature required for a certain kind of material the known irons are provided with a thermostatic device which controls the temperature of the heating plate (normally lying between 100.degree. and 220.degree. C.) and is maintaining this at the pre-selected level.